The Revo has the best enhancement of shifting (I think the second revision is 50% less throw length and 20% less knob height and if you have to cuts you can cut it up to make it 60%) but I've heard that a lot of people have had them break....

Comptech, DC Sports, Neuspeed and a bunch of other companies make adapters that decrease shift length by about 20%, but I think they're main drawback is that they don't do that much....